1 //===-- AppleObjCTrampolineHandler.cpp ------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "AppleObjCTrampolineHandler.h" 10 #include "AppleThreadPlanStepThroughObjCTrampoline.h" 11 12 #include "Plugins/TypeSystem/Clang/TypeSystemClang.h" 13 #include "lldb/Breakpoint/StoppointCallbackContext.h" 14 #include "lldb/Core/Debugger.h" 15 #include "lldb/Core/Module.h" 16 #include "lldb/Core/StreamFile.h" 17 #include "lldb/Core/Value.h" 18 #include "lldb/Expression/DiagnosticManager.h" 19 #include "lldb/Expression/FunctionCaller.h" 20 #include "lldb/Expression/UserExpression.h" 21 #include "lldb/Expression/UtilityFunction.h" 22 #include "lldb/Symbol/Symbol.h" 23 #include "lldb/Target/ABI.h" 24 #include "lldb/Target/ExecutionContext.h" 25 #include "lldb/Target/Process.h" 26 #include "lldb/Target/RegisterContext.h" 27 #include "lldb/Target/Target.h" 28 #include "lldb/Target/Thread.h" 29 #include "lldb/Target/ThreadPlanRunToAddress.h" 30 #include "lldb/Utility/ConstString.h" 31 #include "lldb/Utility/FileSpec.h" 32 #include "lldb/Utility/Log.h" 33 34 #include "llvm/ADT/STLExtras.h" 35 36 #include "Plugins/LanguageRuntime/ObjC/ObjCLanguageRuntime.h" 37 38 #include <memory> 39 40 using namespace lldb; 41 using namespace lldb_private; 42 43 const char *AppleObjCTrampolineHandler::g_lookup_implementation_function_name = 44 "__lldb_objc_find_implementation_for_selector"; 45 const char *AppleObjCTrampolineHandler:: 46 g_lookup_implementation_with_stret_function_code = 47 " \n\ 48 extern \"C\" \n\ 49 { \n\ 50 extern void *class_getMethodImplementation(void *objc_class, void *sel); \n\ 51 extern void *class_getMethodImplementation_stret(void *objc_class, \n\ 52 void *sel); \n\ 53 extern void * object_getClass (id object); \n\ 54 extern void * sel_getUid(char *name); \n\ 55 extern int printf(const char *format, ...); \n\ 56 } \n\ 57 extern \"C\" void * __lldb_objc_find_implementation_for_selector ( \n\ 58 void *object, \n\ 59 void *sel, \n\ 60 int is_stret, \n\ 61 int is_super, \n\ 62 int is_super2, \n\ 63 int is_fixup, \n\ 64 int is_fixed, \n\ 65 int debug) \n\ 66 { \n\ 67 struct __lldb_imp_return_struct \n\ 68 { \n\ 69 void *class_addr; \n\ 70 void *sel_addr; \n\ 71 void *impl_addr; \n\ 72 }; \n\ 73 \n\ 74 struct __lldb_objc_class { \n\ 75 void *isa; \n\ 76 void *super_ptr; \n\ 77 }; \n\ 78 struct __lldb_objc_super { \n\ 79 void *receiver; \n\ 80 struct __lldb_objc_class *class_ptr; \n\ 81 }; \n\ 82 struct __lldb_msg_ref { \n\ 83 void *dont_know; \n\ 84 void *sel; \n\ 85 }; \n\ 86 \n\ 87 struct __lldb_imp_return_struct return_struct; \n\ 88 \n\ 89 if (debug) \n\ 90 printf (\"\\n*** Called with obj: 0x%p sel: 0x%p is_stret: %d is_super: %d, \"\n\ 91 \"is_super2: %d, is_fixup: %d, is_fixed: %d\\n\", \n\ 92 object, sel, is_stret, is_super, is_super2, is_fixup, is_fixed);\n\ 93 if (is_super) \n\ 94 { \n\ 95 if (is_super2) \n\ 96 { \n\ 97 return_struct.class_addr = ((__lldb_objc_super *) object)->class_ptr->super_ptr;\n\ 98 } \n\ 99 else \n\ 100 { \n\ 101 return_struct.class_addr = ((__lldb_objc_super *) object)->class_ptr;\n\ 102 } \n\ 103 } \n\ 104 else \n\ 105 { \n\ 106 // This code seems a little funny, but has its reasons... \n\ 107 \n\ 108 // The call to [object class] is here because if this is a \n\ 109 // class, and has not been called into yet, we need to do \n\ 110 // something to force the class to initialize itself. \n\ 111 // Then the call to object_getClass will actually return the \n\ 112 // correct class, either the class if object is a class \n\ 113 // instance, or the meta-class if it is a class pointer. \n\ 114 void *class_ptr = (void *) [(id) object class]; \n\ 115 return_struct.class_addr = (id) object_getClass((id) object); \n\ 116 if (debug) \n\ 117 { \n\ 118 if (class_ptr == object) \n\ 119 { \n\ 120 printf (\"Found a class object, need to use the meta class %p -> %p\\n\",\n\ 121 class_ptr, return_struct.class_addr); \n\ 122 } \n\ 123 else \n\ 124 { \n\ 125 printf (\"[object class] returned: %p object_getClass: %p.\\n\", \n\ 126 class_ptr, return_struct.class_addr); \n\ 127 } \n\ 128 } \n\ 129 } \n\ 130 \n\ 131 if (is_fixup) \n\ 132 { \n\ 133 if (is_fixed) \n\ 134 { \n\ 135 return_struct.sel_addr = ((__lldb_msg_ref *) sel)->sel; \n\ 136 } \n\ 137 else \n\ 138 { \n\ 139 char *sel_name = (char *) ((__lldb_msg_ref *) sel)->sel; \n\ 140 return_struct.sel_addr = sel_getUid (sel_name); \n\ 141 if (debug) \n\ 142 printf (\"\\n*** Got fixed up selector: %p for name %s.\\n\",\n\ 143 return_struct.sel_addr, sel_name); \n\ 144 } \n\ 145 } \n\ 146 else \n\ 147 { \n\ 148 return_struct.sel_addr = sel; \n\ 149 } \n\ 150 \n\ 151 if (is_stret) \n\ 152 { \n\ 153 return_struct.impl_addr = \n\ 154 class_getMethodImplementation_stret (return_struct.class_addr, \n\ 155 return_struct.sel_addr); \n\ 156 } \n\ 157 else \n\ 158 { \n\ 159 return_struct.impl_addr = \n\ 160 class_getMethodImplementation (return_struct.class_addr, \n\ 161 return_struct.sel_addr); \n\ 162 } \n\ 163 if (debug) \n\ 164 printf (\"\\n*** Returning implementation: %p.\\n\", \n\ 165 return_struct.impl_addr); \n\ 166 \n\ 167 return return_struct.impl_addr; \n\ 168 } \n\ 169 "; 170 const char * 171 AppleObjCTrampolineHandler::g_lookup_implementation_no_stret_function_code = 172 " \n\ 173 extern \"C\" \n\ 174 { \n\ 175 extern void *class_getMethodImplementation(void *objc_class, void *sel); \n\ 176 extern void * object_getClass (id object); \n\ 177 extern void * sel_getUid(char *name); \n\ 178 extern int printf(const char *format, ...); \n\ 179 } \n\ 180 extern \"C\" void * __lldb_objc_find_implementation_for_selector (void *object, \n\ 181 void *sel, \n\ 182 int is_stret, \n\ 183 int is_super, \n\ 184 int is_super2, \n\ 185 int is_fixup, \n\ 186 int is_fixed, \n\ 187 int debug) \n\ 188 { \n\ 189 struct __lldb_imp_return_struct \n\ 190 { \n\ 191 void *class_addr; \n\ 192 void *sel_addr; \n\ 193 void *impl_addr; \n\ 194 }; \n\ 195 \n\ 196 struct __lldb_objc_class { \n\ 197 void *isa; \n\ 198 void *super_ptr; \n\ 199 }; \n\ 200 struct __lldb_objc_super { \n\ 201 void *receiver; \n\ 202 struct __lldb_objc_class *class_ptr; \n\ 203 }; \n\ 204 struct __lldb_msg_ref { \n\ 205 void *dont_know; \n\ 206 void *sel; \n\ 207 }; \n\ 208 \n\ 209 struct __lldb_imp_return_struct return_struct; \n\ 210 \n\ 211 if (debug) \n\ 212 printf (\"\\n*** Called with obj: 0x%p sel: 0x%p is_stret: %d is_super: %d, \" \n\ 213 \"is_super2: %d, is_fixup: %d, is_fixed: %d\\n\", \n\ 214 object, sel, is_stret, is_super, is_super2, is_fixup, is_fixed); \n\ 215 if (is_super) \n\ 216 { \n\ 217 if (is_super2) \n\ 218 { \n\ 219 return_struct.class_addr = ((__lldb_objc_super *) object)->class_ptr->super_ptr; \n\ 220 } \n\ 221 else \n\ 222 { \n\ 223 return_struct.class_addr = ((__lldb_objc_super *) object)->class_ptr; \n\ 224 } \n\ 225 } \n\ 226 else \n\ 227 { \n\ 228 // This code seems a little funny, but has its reasons... \n\ 229 // The call to [object class] is here because if this is a class, and has not been called into \n\ 230 // yet, we need to do something to force the class to initialize itself. \n\ 231 // Then the call to object_getClass will actually return the correct class, either the class \n\ 232 // if object is a class instance, or the meta-class if it is a class pointer. \n\ 233 void *class_ptr = (void *) [(id) object class]; \n\ 234 return_struct.class_addr = (id) object_getClass((id) object); \n\ 235 if (debug) \n\ 236 { \n\ 237 if (class_ptr == object) \n\ 238 { \n\ 239 printf (\"Found a class object, need to return the meta class %p -> %p\\n\", \n\ 240 class_ptr, return_struct.class_addr); \n\ 241 } \n\ 242 else \n\ 243 { \n\ 244 printf (\"[object class] returned: %p object_getClass: %p.\\n\", \n\ 245 class_ptr, return_struct.class_addr); \n\ 246 } \n\ 247 } \n\ 248 } \n\ 249 \n\ 250 if (is_fixup) \n\ 251 { \n\ 252 if (is_fixed) \n\ 253 { \n\ 254 return_struct.sel_addr = ((__lldb_msg_ref *) sel)->sel; \n\ 255 } \n\ 256 else \n\ 257 { \n\ 258 char *sel_name = (char *) ((__lldb_msg_ref *) sel)->sel; \n\ 259 return_struct.sel_addr = sel_getUid (sel_name); \n\ 260 if (debug) \n\ 261 printf (\"\\n*** Got fixed up selector: %p for name %s.\\n\",\n\ 262 return_struct.sel_addr, sel_name); \n\ 263 } \n\ 264 } \n\ 265 else \n\ 266 { \n\ 267 return_struct.sel_addr = sel; \n\ 268 } \n\ 269 \n\ 270 return_struct.impl_addr = \n\ 271 class_getMethodImplementation (return_struct.class_addr, \n\ 272 return_struct.sel_addr); \n\ 273 if (debug) \n\ 274 printf (\"\\n*** Returning implementation: 0x%p.\\n\", \n\ 275 return_struct.impl_addr); \n\ 276 \n\ 277 return return_struct.impl_addr; \n\ 278 } \n\ 279 "; 280 281 AppleObjCTrampolineHandler::AppleObjCVTables::VTableRegion::VTableRegion( 282 AppleObjCVTables *owner, lldb::addr_t header_addr) 283 : m_valid(true), m_owner(owner), m_header_addr(header_addr), 284 m_code_start_addr(0), m_code_end_addr(0), m_next_region(0) { 285 SetUpRegion(); 286 } 287 288 AppleObjCTrampolineHandler::~AppleObjCTrampolineHandler() {} 289 290 void AppleObjCTrampolineHandler::AppleObjCVTables::VTableRegion::SetUpRegion() { 291 // The header looks like: 292 // 293 // uint16_t headerSize 294 // uint16_t descSize 295 // uint32_t descCount 296 // void * next 297 // 298 // First read in the header: 299 300 char memory_buffer[16]; 301 ProcessSP process_sp = m_owner->GetProcessSP(); 302 if (!process_sp) 303 return; 304 DataExtractor data(memory_buffer, sizeof(memory_buffer), 305 process_sp->GetByteOrder(), 306 process_sp->GetAddressByteSize()); 307 size_t actual_size = 8 + process_sp->GetAddressByteSize(); 308 Status error; 309 size_t bytes_read = 310 process_sp->ReadMemory(m_header_addr, memory_buffer, actual_size, error); 311 if (bytes_read != actual_size) { 312 m_valid = false; 313 return; 314 } 315 316 lldb::offset_t offset = 0; 317 const uint16_t header_size = data.GetU16(&offset); 318 const uint16_t descriptor_size = data.GetU16(&offset); 319 const size_t num_descriptors = data.GetU32(&offset); 320 321 m_next_region = data.GetAddress(&offset); 322 323 // If the header size is 0, that means we've come in too early before this 324 // data is set up. 325 // Set ourselves as not valid, and continue. 326 if (header_size == 0 || num_descriptors == 0) { 327 m_valid = false; 328 return; 329 } 330 331 // Now read in all the descriptors: 332 // The descriptor looks like: 333 // 334 // uint32_t offset 335 // uint32_t flags 336 // 337 // Where offset is either 0 - in which case it is unused, or it is 338 // the offset of the vtable code from the beginning of the 339 // descriptor record. Below, we'll convert that into an absolute 340 // code address, since I don't want to have to compute it over and 341 // over. 342 343 // Ingest the whole descriptor array: 344 const lldb::addr_t desc_ptr = m_header_addr + header_size; 345 const size_t desc_array_size = num_descriptors * descriptor_size; 346 DataBufferSP data_sp(new DataBufferHeap(desc_array_size, '\0')); 347 uint8_t *dst = (uint8_t *)data_sp->GetBytes(); 348 349 DataExtractor desc_extractor(dst, desc_array_size, process_sp->GetByteOrder(), 350 process_sp->GetAddressByteSize()); 351 bytes_read = process_sp->ReadMemory(desc_ptr, dst, desc_array_size, error); 352 if (bytes_read != desc_array_size) { 353 m_valid = false; 354 return; 355 } 356 357 // The actual code for the vtables will be laid out consecutively, so I also 358 // compute the start and end of the whole code block. 359 360 offset = 0; 361 m_code_start_addr = 0; 362 m_code_end_addr = 0; 363 364 for (size_t i = 0; i < num_descriptors; i++) { 365 lldb::addr_t start_offset = offset; 366 uint32_t voffset = desc_extractor.GetU32(&offset); 367 uint32_t flags = desc_extractor.GetU32(&offset); 368 lldb::addr_t code_addr = desc_ptr + start_offset + voffset; 369 m_descriptors.push_back(VTableDescriptor(flags, code_addr)); 370 371 if (m_code_start_addr == 0 || code_addr < m_code_start_addr) 372 m_code_start_addr = code_addr; 373 if (code_addr > m_code_end_addr) 374 m_code_end_addr = code_addr; 375 376 offset = start_offset + descriptor_size; 377 } 378 // Finally, a little bird told me that all the vtable code blocks 379 // are the same size. Let's compute the blocks and if they are all 380 // the same add the size to the code end address: 381 lldb::addr_t code_size = 0; 382 bool all_the_same = true; 383 for (size_t i = 0; i < num_descriptors - 1; i++) { 384 lldb::addr_t this_size = 385 m_descriptors[i + 1].code_start - m_descriptors[i].code_start; 386 if (code_size == 0) 387 code_size = this_size; 388 else { 389 if (this_size != code_size) 390 all_the_same = false; 391 if (this_size > code_size) 392 code_size = this_size; 393 } 394 } 395 if (all_the_same) 396 m_code_end_addr += code_size; 397 } 398 399 bool AppleObjCTrampolineHandler::AppleObjCVTables::VTableRegion:: 400 AddressInRegion(lldb::addr_t addr, uint32_t &flags) { 401 if (!IsValid()) 402 return false; 403 404 if (addr < m_code_start_addr || addr > m_code_end_addr) 405 return false; 406 407 std::vector<VTableDescriptor>::iterator pos, end = m_descriptors.end(); 408 for (pos = m_descriptors.begin(); pos != end; pos++) { 409 if (addr <= (*pos).code_start) { 410 flags = (*pos).flags; 411 return true; 412 } 413 } 414 return false; 415 } 416 417 void AppleObjCTrampolineHandler::AppleObjCVTables::VTableRegion::Dump( 418 Stream &s) { 419 s.Printf("Header addr: 0x%" PRIx64 " Code start: 0x%" PRIx64 420 " Code End: 0x%" PRIx64 " Next: 0x%" PRIx64 "\n", 421 m_header_addr, m_code_start_addr, m_code_end_addr, m_next_region); 422 size_t num_elements = m_descriptors.size(); 423 for (size_t i = 0; i < num_elements; i++) { 424 s.Indent(); 425 s.Printf("Code start: 0x%" PRIx64 " Flags: %d\n", 426 m_descriptors[i].code_start, m_descriptors[i].flags); 427 } 428 } 429 430 AppleObjCTrampolineHandler::AppleObjCVTables::AppleObjCVTables( 431 const ProcessSP &process_sp, const ModuleSP &objc_module_sp) 432 : m_process_wp(), m_trampoline_header(LLDB_INVALID_ADDRESS), 433 m_trampolines_changed_bp_id(LLDB_INVALID_BREAK_ID), 434 m_objc_module_sp(objc_module_sp) { 435 if (process_sp) 436 m_process_wp = process_sp; 437 } 438 439 AppleObjCTrampolineHandler::AppleObjCVTables::~AppleObjCVTables() { 440 ProcessSP process_sp = GetProcessSP(); 441 if (process_sp) { 442 if (m_trampolines_changed_bp_id != LLDB_INVALID_BREAK_ID) 443 process_sp->GetTarget().RemoveBreakpointByID(m_trampolines_changed_bp_id); 444 } 445 } 446 447 bool AppleObjCTrampolineHandler::AppleObjCVTables::InitializeVTableSymbols() { 448 if (m_trampoline_header != LLDB_INVALID_ADDRESS) 449 return true; 450 451 ProcessSP process_sp = GetProcessSP(); 452 if (process_sp) { 453 Target &target = process_sp->GetTarget(); 454 455 const ModuleList &target_modules = target.GetImages(); 456 std::lock_guard<std::recursive_mutex> guard(target_modules.GetMutex()); 457 size_t num_modules = target_modules.GetSize(); 458 if (!m_objc_module_sp) { 459 for (size_t i = 0; i < num_modules; i++) { 460 if (ObjCLanguageRuntime::Get(*process_sp) 461 ->IsModuleObjCLibrary( 462 target_modules.GetModuleAtIndexUnlocked(i))) { 463 m_objc_module_sp = target_modules.GetModuleAtIndexUnlocked(i); 464 break; 465 } 466 } 467 } 468 469 if (m_objc_module_sp) { 470 ConstString trampoline_name("gdb_objc_trampolines"); 471 const Symbol *trampoline_symbol = 472 m_objc_module_sp->FindFirstSymbolWithNameAndType(trampoline_name, 473 eSymbolTypeData); 474 if (trampoline_symbol != nullptr) { 475 m_trampoline_header = trampoline_symbol->GetLoadAddress(&target); 476 if (m_trampoline_header == LLDB_INVALID_ADDRESS) 477 return false; 478 479 // Next look up the "changed" symbol and set a breakpoint on that... 480 ConstString changed_name("gdb_objc_trampolines_changed"); 481 const Symbol *changed_symbol = 482 m_objc_module_sp->FindFirstSymbolWithNameAndType(changed_name, 483 eSymbolTypeCode); 484 if (changed_symbol != nullptr) { 485 const Address changed_symbol_addr = changed_symbol->GetAddress(); 486 if (!changed_symbol_addr.IsValid()) 487 return false; 488 489 lldb::addr_t changed_addr = 490 changed_symbol_addr.GetOpcodeLoadAddress(&target); 491 if (changed_addr != LLDB_INVALID_ADDRESS) { 492 BreakpointSP trampolines_changed_bp_sp = 493 target.CreateBreakpoint(changed_addr, true, false); 494 if (trampolines_changed_bp_sp) { 495 m_trampolines_changed_bp_id = trampolines_changed_bp_sp->GetID(); 496 trampolines_changed_bp_sp->SetCallback(RefreshTrampolines, this, 497 true); 498 trampolines_changed_bp_sp->SetBreakpointKind( 499 "objc-trampolines-changed"); 500 return true; 501 } 502 } 503 } 504 } 505 } 506 } 507 return false; 508 } 509 510 bool AppleObjCTrampolineHandler::AppleObjCVTables::RefreshTrampolines( 511 void *baton, StoppointCallbackContext *context, lldb::user_id_t break_id, 512 lldb::user_id_t break_loc_id) { 513 AppleObjCVTables *vtable_handler = (AppleObjCVTables *)baton; 514 if (vtable_handler->InitializeVTableSymbols()) { 515 // The Update function is called with the address of an added region. So we 516 // grab that address, and 517 // feed it into ReadRegions. Of course, our friend the ABI will get the 518 // values for us. 519 ExecutionContext exe_ctx(context->exe_ctx_ref); 520 Process *process = exe_ctx.GetProcessPtr(); 521 const ABI *abi = process->GetABI().get(); 522 523 TypeSystemClang *clang_ast_context = 524 TypeSystemClang::GetScratch(process->GetTarget()); 525 if (!clang_ast_context) 526 return false; 527 528 ValueList argument_values; 529 Value input_value; 530 CompilerType clang_void_ptr_type = 531 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType(); 532 533 input_value.SetValueType(Value::eValueTypeScalar); 534 // input_value.SetContext (Value::eContextTypeClangType, 535 // clang_void_ptr_type); 536 input_value.SetCompilerType(clang_void_ptr_type); 537 argument_values.PushValue(input_value); 538 539 bool success = 540 abi->GetArgumentValues(exe_ctx.GetThreadRef(), argument_values); 541 if (!success) 542 return false; 543 544 // Now get a pointer value from the zeroth argument. 545 Status error; 546 DataExtractor data; 547 error = argument_values.GetValueAtIndex(0)->GetValueAsData(&exe_ctx, data, 548 nullptr); 549 lldb::offset_t offset = 0; 550 lldb::addr_t region_addr = data.GetAddress(&offset); 551 552 if (region_addr != 0) 553 vtable_handler->ReadRegions(region_addr); 554 } 555 return false; 556 } 557 558 bool AppleObjCTrampolineHandler::AppleObjCVTables::ReadRegions() { 559 // The no argument version reads the start region from the value of 560 // the gdb_regions_header, and gets started from there. 561 562 m_regions.clear(); 563 if (!InitializeVTableSymbols()) 564 return false; 565 Status error; 566 ProcessSP process_sp = GetProcessSP(); 567 if (process_sp) { 568 lldb::addr_t region_addr = 569 process_sp->ReadPointerFromMemory(m_trampoline_header, error); 570 if (error.Success()) 571 return ReadRegions(region_addr); 572 } 573 return false; 574 } 575 576 bool AppleObjCTrampolineHandler::AppleObjCVTables::ReadRegions( 577 lldb::addr_t region_addr) { 578 ProcessSP process_sp = GetProcessSP(); 579 if (!process_sp) 580 return false; 581 582 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP)); 583 584 // We aren't starting at the trampoline symbol. 585 InitializeVTableSymbols(); 586 lldb::addr_t next_region = region_addr; 587 588 // Read in the sizes of the headers. 589 while (next_region != 0) { 590 m_regions.push_back(VTableRegion(this, next_region)); 591 if (!m_regions.back().IsValid()) { 592 m_regions.clear(); 593 return false; 594 } 595 if (log) { 596 StreamString s; 597 m_regions.back().Dump(s); 598 LLDB_LOGF(log, "Read vtable region: \n%s", s.GetData()); 599 } 600 601 next_region = m_regions.back().GetNextRegionAddr(); 602 } 603 604 return true; 605 } 606 607 bool AppleObjCTrampolineHandler::AppleObjCVTables::IsAddressInVTables( 608 lldb::addr_t addr, uint32_t &flags) { 609 region_collection::iterator pos, end = m_regions.end(); 610 for (pos = m_regions.begin(); pos != end; pos++) { 611 if ((*pos).AddressInRegion(addr, flags)) 612 return true; 613 } 614 return false; 615 } 616 617 const AppleObjCTrampolineHandler::DispatchFunction 618 AppleObjCTrampolineHandler::g_dispatch_functions[] = { 619 // NAME STRET SUPER SUPER2 FIXUP TYPE 620 {"objc_msgSend", false, false, false, DispatchFunction::eFixUpNone}, 621 {"objc_msgSend_fixup", false, false, false, 622 DispatchFunction::eFixUpToFix}, 623 {"objc_msgSend_fixedup", false, false, false, 624 DispatchFunction::eFixUpFixed}, 625 {"objc_msgSend_stret", true, false, false, 626 DispatchFunction::eFixUpNone}, 627 {"objc_msgSend_stret_fixup", true, false, false, 628 DispatchFunction::eFixUpToFix}, 629 {"objc_msgSend_stret_fixedup", true, false, false, 630 DispatchFunction::eFixUpFixed}, 631 {"objc_msgSend_fpret", false, false, false, 632 DispatchFunction::eFixUpNone}, 633 {"objc_msgSend_fpret_fixup", false, false, false, 634 DispatchFunction::eFixUpToFix}, 635 {"objc_msgSend_fpret_fixedup", false, false, false, 636 DispatchFunction::eFixUpFixed}, 637 {"objc_msgSend_fp2ret", false, false, true, 638 DispatchFunction::eFixUpNone}, 639 {"objc_msgSend_fp2ret_fixup", false, false, true, 640 DispatchFunction::eFixUpToFix}, 641 {"objc_msgSend_fp2ret_fixedup", false, false, true, 642 DispatchFunction::eFixUpFixed}, 643 {"objc_msgSendSuper", false, true, false, DispatchFunction::eFixUpNone}, 644 {"objc_msgSendSuper_stret", true, true, false, 645 DispatchFunction::eFixUpNone}, 646 {"objc_msgSendSuper2", false, true, true, DispatchFunction::eFixUpNone}, 647 {"objc_msgSendSuper2_fixup", false, true, true, 648 DispatchFunction::eFixUpToFix}, 649 {"objc_msgSendSuper2_fixedup", false, true, true, 650 DispatchFunction::eFixUpFixed}, 651 {"objc_msgSendSuper2_stret", true, true, true, 652 DispatchFunction::eFixUpNone}, 653 {"objc_msgSendSuper2_stret_fixup", true, true, true, 654 DispatchFunction::eFixUpToFix}, 655 {"objc_msgSendSuper2_stret_fixedup", true, true, true, 656 DispatchFunction::eFixUpFixed}, 657 }; 658 659 // This is the table of ObjC "accelerated dispatch" functions. They are a set 660 // of objc methods that are "seldom overridden" and so the compiler replaces the 661 // objc_msgSend with a call to one of the dispatch functions. That will check 662 // whether the method has been overridden, and directly call the Foundation 663 // implementation if not. 664 // This table is supposed to be complete. If ones get added in the future, we 665 // will have to add them to the table. 666 const char *AppleObjCTrampolineHandler::g_opt_dispatch_names[] = { 667 "objc_alloc", 668 "objc_autorelease", 669 "objc_release", 670 "objc_retain", 671 "objc_alloc_init", 672 "objc_allocWithZone", 673 "objc_opt_class", 674 "objc_opt_isKindOfClass", 675 "objc_opt_new", 676 "objc_opt_respondsToSelector", 677 "objc_opt_self", 678 }; 679 680 AppleObjCTrampolineHandler::AppleObjCTrampolineHandler( 681 const ProcessSP &process_sp, const ModuleSP &objc_module_sp) 682 : m_process_wp(), m_objc_module_sp(objc_module_sp), 683 m_lookup_implementation_function_code(nullptr), 684 m_impl_fn_addr(LLDB_INVALID_ADDRESS), 685 m_impl_stret_fn_addr(LLDB_INVALID_ADDRESS), 686 m_msg_forward_addr(LLDB_INVALID_ADDRESS) { 687 if (process_sp) 688 m_process_wp = process_sp; 689 // Look up the known resolution functions: 690 691 ConstString get_impl_name("class_getMethodImplementation"); 692 ConstString get_impl_stret_name("class_getMethodImplementation_stret"); 693 ConstString msg_forward_name("_objc_msgForward"); 694 ConstString msg_forward_stret_name("_objc_msgForward_stret"); 695 696 Target *target = process_sp ? &process_sp->GetTarget() : nullptr; 697 const Symbol *class_getMethodImplementation = 698 m_objc_module_sp->FindFirstSymbolWithNameAndType(get_impl_name, 699 eSymbolTypeCode); 700 const Symbol *class_getMethodImplementation_stret = 701 m_objc_module_sp->FindFirstSymbolWithNameAndType(get_impl_stret_name, 702 eSymbolTypeCode); 703 const Symbol *msg_forward = m_objc_module_sp->FindFirstSymbolWithNameAndType( 704 msg_forward_name, eSymbolTypeCode); 705 const Symbol *msg_forward_stret = 706 m_objc_module_sp->FindFirstSymbolWithNameAndType(msg_forward_stret_name, 707 eSymbolTypeCode); 708 709 if (class_getMethodImplementation) 710 m_impl_fn_addr = 711 class_getMethodImplementation->GetAddress().GetOpcodeLoadAddress( 712 target); 713 if (class_getMethodImplementation_stret) 714 m_impl_stret_fn_addr = 715 class_getMethodImplementation_stret->GetAddress().GetOpcodeLoadAddress( 716 target); 717 if (msg_forward) 718 m_msg_forward_addr = msg_forward->GetAddress().GetOpcodeLoadAddress(target); 719 if (msg_forward_stret) 720 m_msg_forward_stret_addr = 721 msg_forward_stret->GetAddress().GetOpcodeLoadAddress(target); 722 723 // FIXME: Do some kind of logging here. 724 if (m_impl_fn_addr == LLDB_INVALID_ADDRESS) { 725 // If we can't even find the ordinary get method implementation function, 726 // then we aren't going to be able to 727 // step through any method dispatches. Warn to that effect and get out of 728 // here. 729 if (process_sp->CanJIT()) { 730 process_sp->GetTarget().GetDebugger().GetErrorStream().Printf( 731 "Could not find implementation lookup function \"%s\"" 732 " step in through ObjC method dispatch will not work.\n", 733 get_impl_name.AsCString()); 734 } 735 return; 736 } else if (m_impl_stret_fn_addr == LLDB_INVALID_ADDRESS) { 737 // It there is no stret return lookup function, assume that it is the same 738 // as the straight lookup: 739 m_impl_stret_fn_addr = m_impl_fn_addr; 740 // Also we will use the version of the lookup code that doesn't rely on the 741 // stret version of the function. 742 m_lookup_implementation_function_code = 743 g_lookup_implementation_no_stret_function_code; 744 } else { 745 m_lookup_implementation_function_code = 746 g_lookup_implementation_with_stret_function_code; 747 } 748 749 // Look up the addresses for the objc dispatch functions and cache 750 // them. For now I'm inspecting the symbol names dynamically to 751 // figure out how to dispatch to them. If it becomes more 752 // complicated than this we can turn the g_dispatch_functions char * 753 // array into a template table, and populate the DispatchFunction 754 // map from there. 755 756 for (size_t i = 0; i != llvm::array_lengthof(g_dispatch_functions); i++) { 757 ConstString name_const_str(g_dispatch_functions[i].name); 758 const Symbol *msgSend_symbol = 759 m_objc_module_sp->FindFirstSymbolWithNameAndType(name_const_str, 760 eSymbolTypeCode); 761 if (msgSend_symbol && msgSend_symbol->ValueIsAddress()) { 762 // FIXME: Make g_dispatch_functions static table of 763 // DispatchFunctions, and have the map be address->index. 764 // Problem is we also need to lookup the dispatch function. For 765 // now we could have a side table of stret & non-stret dispatch 766 // functions. If that's as complex as it gets, we're fine. 767 768 lldb::addr_t sym_addr = 769 msgSend_symbol->GetAddressRef().GetOpcodeLoadAddress(target); 770 771 m_msgSend_map.insert(std::pair<lldb::addr_t, int>(sym_addr, i)); 772 } 773 } 774 775 // Similarly, cache the addresses of the "optimized dispatch" function. 776 for (size_t i = 0; i != llvm::array_lengthof(g_opt_dispatch_names); i++) { 777 ConstString name_const_str(g_opt_dispatch_names[i]); 778 const Symbol *msgSend_symbol = 779 m_objc_module_sp->FindFirstSymbolWithNameAndType(name_const_str, 780 eSymbolTypeCode); 781 if (msgSend_symbol && msgSend_symbol->ValueIsAddress()) { 782 lldb::addr_t sym_addr = 783 msgSend_symbol->GetAddressRef().GetOpcodeLoadAddress(target); 784 785 m_opt_dispatch_map.emplace(sym_addr, i); 786 } 787 } 788 789 // Build our vtable dispatch handler here: 790 m_vtables_up = 791 std::make_unique<AppleObjCVTables>(process_sp, m_objc_module_sp); 792 if (m_vtables_up) 793 m_vtables_up->ReadRegions(); 794 } 795 796 lldb::addr_t 797 AppleObjCTrampolineHandler::SetupDispatchFunction(Thread &thread, 798 ValueList &dispatch_values) { 799 ThreadSP thread_sp(thread.shared_from_this()); 800 ExecutionContext exe_ctx(thread_sp); 801 DiagnosticManager diagnostics; 802 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP)); 803 804 lldb::addr_t args_addr = LLDB_INVALID_ADDRESS; 805 FunctionCaller *impl_function_caller = nullptr; 806 807 // Scope for mutex locker: 808 { 809 std::lock_guard<std::mutex> guard(m_impl_function_mutex); 810 811 // First stage is to make the ClangUtility to hold our injected function: 812 813 if (!m_impl_code) { 814 if (m_lookup_implementation_function_code != nullptr) { 815 Status error; 816 m_impl_code.reset(exe_ctx.GetTargetRef().GetUtilityFunctionForLanguage( 817 m_lookup_implementation_function_code, eLanguageTypeObjC, 818 g_lookup_implementation_function_name, error)); 819 if (error.Fail()) { 820 LLDB_LOGF( 821 log, 822 "Failed to get Utility Function for implementation lookup: %s.", 823 error.AsCString()); 824 m_impl_code.reset(); 825 return args_addr; 826 } 827 828 if (!m_impl_code->Install(diagnostics, exe_ctx)) { 829 if (log) { 830 LLDB_LOGF(log, "Failed to install implementation lookup."); 831 diagnostics.Dump(log); 832 } 833 m_impl_code.reset(); 834 return args_addr; 835 } 836 } else { 837 LLDB_LOGF(log, "No method lookup implementation code."); 838 return LLDB_INVALID_ADDRESS; 839 } 840 841 // Next make the runner function for our implementation utility function. 842 TypeSystemClang *clang_ast_context = 843 TypeSystemClang::GetScratch(thread.GetProcess()->GetTarget()); 844 if (!clang_ast_context) 845 return LLDB_INVALID_ADDRESS; 846 847 CompilerType clang_void_ptr_type = 848 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType(); 849 Status error; 850 851 impl_function_caller = m_impl_code->MakeFunctionCaller( 852 clang_void_ptr_type, dispatch_values, thread_sp, error); 853 if (error.Fail()) { 854 LLDB_LOGF(log, 855 "Error getting function caller for dispatch lookup: \"%s\".", 856 error.AsCString()); 857 return args_addr; 858 } 859 } else { 860 impl_function_caller = m_impl_code->GetFunctionCaller(); 861 } 862 } 863 864 diagnostics.Clear(); 865 866 // Now write down the argument values for this particular call. 867 // This looks like it might be a race condition if other threads 868 // were calling into here, but actually it isn't because we allocate 869 // a new args structure for this call by passing args_addr = 870 // LLDB_INVALID_ADDRESS... 871 872 if (!impl_function_caller->WriteFunctionArguments( 873 exe_ctx, args_addr, dispatch_values, diagnostics)) { 874 if (log) { 875 LLDB_LOGF(log, "Error writing function arguments."); 876 diagnostics.Dump(log); 877 } 878 return args_addr; 879 } 880 881 return args_addr; 882 } 883 884 const AppleObjCTrampolineHandler::DispatchFunction * 885 AppleObjCTrampolineHandler::FindDispatchFunction(lldb::addr_t addr) { 886 MsgsendMap::iterator pos; 887 pos = m_msgSend_map.find(addr); 888 if (pos != m_msgSend_map.end()) { 889 return &g_dispatch_functions[(*pos).second]; 890 } 891 return nullptr; 892 } 893 894 void 895 AppleObjCTrampolineHandler::ForEachDispatchFunction( 896 std::function<void(lldb::addr_t, 897 const DispatchFunction &)> callback) { 898 for (auto elem : m_msgSend_map) { 899 callback(elem.first, g_dispatch_functions[elem.second]); 900 } 901 } 902 903 ThreadPlanSP 904 AppleObjCTrampolineHandler::GetStepThroughDispatchPlan(Thread &thread, 905 bool stop_others) { 906 ThreadPlanSP ret_plan_sp; 907 lldb::addr_t curr_pc = thread.GetRegisterContext()->GetPC(); 908 909 DispatchFunction vtable_dispatch 910 = {"vtable", 0, false, false, DispatchFunction::eFixUpFixed}; 911 912 // First step is to look and see if we are in one of the known ObjC 913 // dispatch functions. We've already compiled a table of same, so 914 // consult it. 915 916 const DispatchFunction *this_dispatch = FindDispatchFunction(curr_pc); 917 918 // Next check to see if we are in a vtable region: 919 920 if (!this_dispatch && m_vtables_up) { 921 uint32_t flags; 922 if (m_vtables_up->IsAddressInVTables(curr_pc, flags)) { 923 vtable_dispatch.stret_return = 924 (flags & AppleObjCVTables::eOBJC_TRAMPOLINE_STRET) == 925 AppleObjCVTables::eOBJC_TRAMPOLINE_STRET; 926 this_dispatch = &vtable_dispatch; 927 } 928 } 929 930 if (this_dispatch) { 931 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP)); 932 933 // We are decoding a method dispatch. First job is to pull the 934 // arguments out: 935 936 lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(0); 937 938 const ABI *abi = nullptr; 939 ProcessSP process_sp(thread.CalculateProcess()); 940 if (process_sp) 941 abi = process_sp->GetABI().get(); 942 if (abi == nullptr) 943 return ret_plan_sp; 944 945 TargetSP target_sp(thread.CalculateTarget()); 946 947 TypeSystemClang *clang_ast_context = TypeSystemClang::GetScratch(*target_sp); 948 if (!clang_ast_context) 949 return ret_plan_sp; 950 951 ValueList argument_values; 952 Value void_ptr_value; 953 CompilerType clang_void_ptr_type = 954 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType(); 955 void_ptr_value.SetValueType(Value::eValueTypeScalar); 956 // void_ptr_value.SetContext (Value::eContextTypeClangType, 957 // clang_void_ptr_type); 958 void_ptr_value.SetCompilerType(clang_void_ptr_type); 959 960 int obj_index; 961 int sel_index; 962 963 // If this is a struct return dispatch, then the first argument is 964 // the return struct pointer, and the object is the second, and 965 // the selector is the third. Otherwise the object is the first 966 // and the selector the second. 967 if (this_dispatch->stret_return) { 968 obj_index = 1; 969 sel_index = 2; 970 argument_values.PushValue(void_ptr_value); 971 argument_values.PushValue(void_ptr_value); 972 argument_values.PushValue(void_ptr_value); 973 } else { 974 obj_index = 0; 975 sel_index = 1; 976 argument_values.PushValue(void_ptr_value); 977 argument_values.PushValue(void_ptr_value); 978 } 979 980 bool success = abi->GetArgumentValues(thread, argument_values); 981 if (!success) 982 return ret_plan_sp; 983 984 lldb::addr_t obj_addr = 985 argument_values.GetValueAtIndex(obj_index)->GetScalar().ULongLong(); 986 if (obj_addr == 0x0) { 987 LLDB_LOGF( 988 log, 989 "Asked to step to dispatch to nil object, returning empty plan."); 990 return ret_plan_sp; 991 } 992 993 ExecutionContext exe_ctx(thread.shared_from_this()); 994 Process *process = exe_ctx.GetProcessPtr(); 995 // isa_addr will store the class pointer that the method is being 996 // dispatched to - so either the class directly or the super class 997 // if this is one of the objc_msgSendSuper flavors. That's mostly 998 // used to look up the class/selector pair in our cache. 999 1000 lldb::addr_t isa_addr = LLDB_INVALID_ADDRESS; 1001 lldb::addr_t sel_addr = 1002 argument_values.GetValueAtIndex(sel_index)->GetScalar().ULongLong(); 1003 1004 // Figure out the class this is being dispatched to and see if 1005 // we've already cached this method call, If so we can push a 1006 // run-to-address plan directly. Otherwise we have to figure out 1007 // where the implementation lives. 1008 1009 if (this_dispatch->is_super) { 1010 if (this_dispatch->is_super2) { 1011 // In the objc_msgSendSuper2 case, we don't get the object 1012 // directly, we get a structure containing the object and the 1013 // class to which the super message is being sent. So we need 1014 // to dig the super out of the class and use that. 1015 1016 Value super_value(*(argument_values.GetValueAtIndex(obj_index))); 1017 super_value.GetScalar() += process->GetAddressByteSize(); 1018 super_value.ResolveValue(&exe_ctx); 1019 1020 if (super_value.GetScalar().IsValid()) { 1021 1022 // isa_value now holds the class pointer. The second word of the 1023 // class pointer is the super-class pointer: 1024 super_value.GetScalar() += process->GetAddressByteSize(); 1025 super_value.ResolveValue(&exe_ctx); 1026 if (super_value.GetScalar().IsValid()) 1027 isa_addr = super_value.GetScalar().ULongLong(); 1028 else { 1029 LLDB_LOGF(log, "Failed to extract the super class value from the " 1030 "class in objc_super."); 1031 } 1032 } else { 1033 LLDB_LOGF(log, "Failed to extract the class value from objc_super."); 1034 } 1035 } else { 1036 // In the objc_msgSendSuper case, we don't get the object 1037 // directly, we get a two element structure containing the 1038 // object and the super class to which the super message is 1039 // being sent. So the class we want is the second element of 1040 // this structure. 1041 1042 Value super_value(*(argument_values.GetValueAtIndex(obj_index))); 1043 super_value.GetScalar() += process->GetAddressByteSize(); 1044 super_value.ResolveValue(&exe_ctx); 1045 1046 if (super_value.GetScalar().IsValid()) { 1047 isa_addr = super_value.GetScalar().ULongLong(); 1048 } else { 1049 LLDB_LOGF(log, "Failed to extract the class value from objc_super."); 1050 } 1051 } 1052 } else { 1053 // In the direct dispatch case, the object->isa is the class pointer we 1054 // want. 1055 1056 // This is a little cheesy, but since object->isa is the first field, 1057 // making the object value a load address value and resolving it will get 1058 // the pointer sized data pointed to by that value... 1059 1060 // Note, it isn't a fatal error not to be able to get the 1061 // address from the object, since this might be a "tagged 1062 // pointer" which isn't a real object, but rather some word 1063 // length encoded dingus. 1064 1065 Value isa_value(*(argument_values.GetValueAtIndex(obj_index))); 1066 1067 isa_value.SetValueType(Value::eValueTypeLoadAddress); 1068 isa_value.ResolveValue(&exe_ctx); 1069 if (isa_value.GetScalar().IsValid()) { 1070 isa_addr = isa_value.GetScalar().ULongLong(); 1071 } else { 1072 LLDB_LOGF(log, "Failed to extract the isa value from object."); 1073 } 1074 } 1075 1076 // Okay, we've got the address of the class for which we're resolving this, 1077 // let's see if it's in our cache: 1078 lldb::addr_t impl_addr = LLDB_INVALID_ADDRESS; 1079 1080 if (isa_addr != LLDB_INVALID_ADDRESS) { 1081 if (log) { 1082 LLDB_LOGF(log, 1083 "Resolving call for class - 0x%" PRIx64 1084 " and selector - 0x%" PRIx64, 1085 isa_addr, sel_addr); 1086 } 1087 ObjCLanguageRuntime *objc_runtime = 1088 ObjCLanguageRuntime::Get(*thread.GetProcess()); 1089 assert(objc_runtime != nullptr); 1090 1091 impl_addr = objc_runtime->LookupInMethodCache(isa_addr, sel_addr); 1092 } 1093 1094 if (impl_addr != LLDB_INVALID_ADDRESS) { 1095 // Yup, it was in the cache, so we can run to that address directly. 1096 1097 LLDB_LOGF(log, "Found implementation address in cache: 0x%" PRIx64, 1098 impl_addr); 1099 1100 ret_plan_sp = std::make_shared<ThreadPlanRunToAddress>(thread, impl_addr, 1101 stop_others); 1102 } else { 1103 // We haven't seen this class/selector pair yet. Look it up. 1104 StreamString errors; 1105 Address impl_code_address; 1106 1107 ValueList dispatch_values; 1108 1109 // We've will inject a little function in the target that takes the 1110 // object, selector and some flags, 1111 // and figures out the implementation. Looks like: 1112 // void *__lldb_objc_find_implementation_for_selector (void *object, 1113 // void *sel, 1114 // int is_stret, 1115 // int is_super, 1116 // int is_super2, 1117 // int is_fixup, 1118 // int is_fixed, 1119 // int debug) 1120 // So set up the arguments for that call. 1121 1122 dispatch_values.PushValue(*(argument_values.GetValueAtIndex(obj_index))); 1123 dispatch_values.PushValue(*(argument_values.GetValueAtIndex(sel_index))); 1124 1125 Value flag_value; 1126 CompilerType clang_int_type = 1127 clang_ast_context->GetBuiltinTypeForEncodingAndBitSize( 1128 lldb::eEncodingSint, 32); 1129 flag_value.SetValueType(Value::eValueTypeScalar); 1130 // flag_value.SetContext (Value::eContextTypeClangType, clang_int_type); 1131 flag_value.SetCompilerType(clang_int_type); 1132 1133 if (this_dispatch->stret_return) 1134 flag_value.GetScalar() = 1; 1135 else 1136 flag_value.GetScalar() = 0; 1137 dispatch_values.PushValue(flag_value); 1138 1139 if (this_dispatch->is_super) 1140 flag_value.GetScalar() = 1; 1141 else 1142 flag_value.GetScalar() = 0; 1143 dispatch_values.PushValue(flag_value); 1144 1145 if (this_dispatch->is_super2) 1146 flag_value.GetScalar() = 1; 1147 else 1148 flag_value.GetScalar() = 0; 1149 dispatch_values.PushValue(flag_value); 1150 1151 switch (this_dispatch->fixedup) { 1152 case DispatchFunction::eFixUpNone: 1153 flag_value.GetScalar() = 0; 1154 dispatch_values.PushValue(flag_value); 1155 dispatch_values.PushValue(flag_value); 1156 break; 1157 case DispatchFunction::eFixUpFixed: 1158 flag_value.GetScalar() = 1; 1159 dispatch_values.PushValue(flag_value); 1160 flag_value.GetScalar() = 1; 1161 dispatch_values.PushValue(flag_value); 1162 break; 1163 case DispatchFunction::eFixUpToFix: 1164 flag_value.GetScalar() = 1; 1165 dispatch_values.PushValue(flag_value); 1166 flag_value.GetScalar() = 0; 1167 dispatch_values.PushValue(flag_value); 1168 break; 1169 } 1170 if (log && log->GetVerbose()) 1171 flag_value.GetScalar() = 1; 1172 else 1173 flag_value.GetScalar() = 0; // FIXME - Set to 0 when debugging is done. 1174 dispatch_values.PushValue(flag_value); 1175 1176 // The step through code might have to fill in the cache, so it 1177 // is not safe to run only one thread. So we override the 1178 // stop_others value passed in to us here: 1179 const bool trampoline_stop_others = false; 1180 ret_plan_sp = std::make_shared<AppleThreadPlanStepThroughObjCTrampoline>( 1181 thread, *this, dispatch_values, isa_addr, sel_addr, 1182 trampoline_stop_others); 1183 if (log) { 1184 StreamString s; 1185 ret_plan_sp->GetDescription(&s, eDescriptionLevelFull); 1186 LLDB_LOGF(log, "Using ObjC step plan: %s.\n", s.GetData()); 1187 } 1188 } 1189 } 1190 1191 // Finally, check if we have hit an "optimized dispatch" function. This will 1192 // either directly call the base implementation or dispatch an objc_msgSend 1193 // if the method has been overridden. So we just do a "step in/step out", 1194 // setting a breakpoint on objc_msgSend, and if we hit the msgSend, we 1195 // will automatically step in again. That's the job of the 1196 // AppleThreadPlanStepThroughDirectDispatch. 1197 if (!this_dispatch && !ret_plan_sp) { 1198 MsgsendMap::iterator pos; 1199 pos = m_opt_dispatch_map.find(curr_pc); 1200 if (pos != m_opt_dispatch_map.end()) { 1201 1202 const char *opt_name = g_opt_dispatch_names[(*pos).second]; 1203 1204 bool trampoline_stop_others = false; 1205 LazyBool step_in_should_stop = eLazyBoolCalculate; 1206 ret_plan_sp = std::make_shared<AppleThreadPlanStepThroughDirectDispatch> ( 1207 thread, *this, opt_name, trampoline_stop_others, step_in_should_stop); 1208 } 1209 } 1210 1211 return ret_plan_sp; 1212 } 1213 1214 FunctionCaller * 1215 AppleObjCTrampolineHandler::GetLookupImplementationFunctionCaller() { 1216 return m_impl_code->GetFunctionCaller(); 1217 } 1218